Paper dye

ABSTRACT

Paper dye of the formula   ESPECIALLY IN LIQUID OR GRANULATED FORM.

United States Patent Frei July 15, 1975 1 PAPER DYE [56] References Cited [76] Inventor: Alfred Frei, Oberwilerstrasse 89, UNITED STATES PATENTS B1n n1ngnBa$e1'Land, 2,148,659 2/1939 Straub et a1 8/42 R Sw1tzerland 2,749,207 6/1956 Menzi et a1. 8/42 R 2,842,536 7/1958 Bauer et al. 260/183 [22] July 1971 3,537,807 12/1970 Streck 8/42 R x [211 PP 165579 FOREIGN PATENTS OR APPLICATIONS 937.879 8/1948 France [30] Foreign Application Priority Data Aug. 5, 1970 Switzerland 11775/70 Primary Examiner-Thomas J. Herbert, Apr. 16, 1971 Switzerland 5562/71 Assistant EXami"@rBru9 Hess [52] US. Cl 8/7; 8/42 R; 8/79;

8/88; 162/162 ABSTRACT [51] Int. Paper dye of the formula N N N N no 3 s so 3 H [58] Field of Search 8/42 R, 79, 88, 91, 7; especially in liquid or granulated form.

PAPER DYE This invention relates to a process for dyeing paper, which is characterized by the use of the dye of the formula The dye is employed preferably as one of its salts, for instance an alkali metal (sodium or potassium) salt or an ammonium salt. The said dye is known and is used for dyeing cotton, on which, as is stated in the literature, it requires heating for fixation.

It has been found that the dye of formula (I) is eminently suitable for paper dyeing. It can be used for dyeing unsized and sized (previously or subsequently sized) paper grades by dipping, coating, spraying or other suitable methods, though it is especially valuable for application in the stock prior to sheet formation.

The dye, which is well soluble in water, gives level dyeings of brilliant reddish blue shade on paper which are notable for their fastness; they are very fast to light, fading tone-in-tone after a long period of exposure, and show similarly good wet fastness properties (alcohol, milk and in particular water fastness).

The dye of formula (I) can be converted into liquid dye preparations containing 1 part by weight of dye, 3-l 1 parts by weight of water and 0.5-3 parts by weight of an amino alcohol, preferably a lower mono-, dior tri-alkanolamine in which each alkanol radical optimally contains 2 or 3 carbon atoms. Mono-, diand triethanolamine and monoand di-iso-propanolamine may be named as examples, of which diethanolamine is especially suitable. These liquid preparations are produced by mixing the stated components, if necessary with heating for a short time; they may contain further additives, such as wetting or dispersing agents.

The new liquid preparations are true solutions or, if concentrated, dispersions (suspensions). They can be employed for dyeing as such or after dilution with water as stock solutions. They are excellent for preparing liquors and pastes for paper dyeing by coating, spraying and dipping methods; however, they are especially well adapted for addition to the stock before conversion into sheet, where they can be metered continuously into the stock stream in the undiluted state.

The dye preparations disclosed herein have the advantage of being easier to handle. The inconvenient dusting that occurs when powder dyes are weighed out is absent. They are storable at room temperature for several months, withstand frost and are immune from mould growth.

The dye of formula (I) can be employed with equal H0 5 o Cu o success in the form of granules, preferably of neutral to alkaline reaction, instead of the liquid form. The granulated preparations of the dye are characterized by containing, with the dye, a maximum of 50 percent of a salt (commonly used in dyeing preparations) which dissoci- Cu -O ates in water and/or a non-hygroscopic dextrin; the aveiage size of the granules is at least 20 microns. Salts of neutral or alkaline reaction which dissociate in water are suitable, but preference is given to the salts of alkali metals, e.g. sodium chloride, potassium chloride, sodium sulphate, potassium sulphate, monosodium and disodium phosphate, sodium and potassium pyrophosphate, sodium and potassium carbonate. Nonhygroscopic dextrins which form no lumps when stirred in aqueous medium are especially suitable, c.f. Ullmann, Enzyklopaedie der technischen Chemie (1965), Vol. XVl, pp. 349352, particularly pp. 35 l352. Dextrins highly soluble in cold water are preferred.

The granulated preparations can be produced with the dye in the form of the moist acid presscake of low salt content (preferably not more than 25 percent of its dry weight of inorganic salts) as obtained in manufacture after acidification. As the granules are best produced by granulation, for example atomization of a neutral or alkaline liquid preparation, if an acid presscake is used, it is best to neutralize it with a strong base, such as lithium, sodium or potassium hydroxide. The granulated dye preparations can be produced by dissolving or suspending the dye, the salt or salts, the dextrin, and (if used) the strong base in two to ten or preferably two and a half to five times the amount of water. If a suspension is formed, it is advantageously homogenized. The solution or suspension is granulated by one of the standard methods, preferably atomization, to give granules averaging at least 20, preferably 40 to microns in size.

The granules are free-flowing and readily soluble in water, so they are excellent for dry addition to paper stocks. They also show good storage stability, especially chemical stability. Compared with the powder dyes used to date they offer the advantages of better wettability and higher solubility in water, this being especially true of preparations containing a maximum of 30 percent of a salt which dissociates in water. This means that stock solutions of concentrated strength can be prepared. Moreover, the granules are easier to handle in weighing out additions for dyeing, and for SO3H 3 4 the dye of the formula (I) is of higher solubility in water with 20 parts of a standardizing agent. for example dex and forms much more stable liquid dyeing preparatrin, and with 300 parts of water in a mixer. The obtions. tained suspension is converted in an atomizer drier into In comparison with the ext compar l dy of granules averaging'40 ,u in size. This dye preparation is mula 5 highly soluble in water.

N I N (II I) H SO H the dye of formula (I) has higher substantivity and on APPLICATION EXAMPLE A Subsequently Sized paper gives dyeings of better wet 100 Parts of chemically bleached sulphite pulp susfastness.

pended in water are beaten to the desired fineness; 3 parts of the preparation described in Example 2 and, after l5 minutes, the sizing agent (which fixes the dyeln the following Examples the parts and percentages are by weight and the temperatures in degrees centigrade' ing) are added. Paper made from this stock is dyed in a reddish blue shade of medium depth which has good EXAMPLE 1 fastness properties. The white water from the paper One part of the dye of the formula machine is colourless.

O Cu 0 H0 5 0 Eu -0 5 N a N N N H0 3 S 3 H in the form of a moist. mineral acid 25 percent press- Comparably good dyeings are obtained when 0.7 part cake is homogeneously mixed with 8 parts of water, 40 of the preparation of Example 3 are used in place of 3 and dissolved by the addition of 0.9 part of diethanolparts f th r aration of E m l 2,

amine, if necessary with heating to This preparation is storable for several months at room tempera- EXAMPLE 4 tum. 53 Parts of the dye of the formula 0- Cu -O EXAMPLE 2 One part of the dye of formula (I) in the form of a in the form of the moist acid presscake obtained on moist mineral acid presscake of 25 percent strength is manufacture, which contains 20 percent dye, 5.5 perdissolved in 3.2 parts of percent diethanolamine socent inorganic salts and 74.5 percent water, are added lution, on which a preparation showing comparably to 300 parts of water, along with 5.5 parts of lithium hygood stability is obtained. oxide and 20 parts of dextrin. Stirring gives a homogeneous suspension which is converted in an atomizer EXAMPLE 3 65 drier into granules averaging 40 microns in size. These Parts of a powder dye containing 82 percent of the are readily soluble in water and very suitable for paper dye of formula (I) and salt are homogeneously mixed dyeing.

APPLICATION EXAMPLE B 100 Parts of chemically bleached sulphite pulp in aqueous suspension are beaten to the required fineness, 0.5 part of the granulated dye preparation of Example 4 are added. followed after minutes by the sizing agent, which fixes the dye. The paper made with this stock has a reddish blue shade of medium depth showing good fastness properties. The white water is colourless.

Having thus disclosed the invention what I claim is: 1. A process for producing colored paper comprising (a) incorporating into paper stock an effective amount of a dye and forming paper from said paper stock or (b) treating paper sheet with an effective amount of a dye, said dye being the compound of the formula or a salt thereof. and said effective amount being an amount sufficient to impart the desired color to the paper.

2. A process according to claim 1 comprising treating paper sheet with an effective amount of the compound of the formula H0 5 Cu -O O SO H or a salt thereof, said effective amount being an amount sufficient to impart the desired color to the paper sheet.

3. A process according to claim 2 comprising applying to paper sheet an effective amount of an aqueous solution of the compound of the formula -Cu -O or a salt thereof, said effective amount being an amount sufficient to impart the desired color to the paper sheet.

4. A process according to claim 1 comprising incorporating into paper stock an effective amount of the compound of the formula -Cu -O SO H Cu -O C u -O or a salt thereof. said effective amount being an amount sufficient to impart the desired color to the paper sheet to be formed. and forming paper sheet from said paper stock.

0 c O 0' CU -O SO H 3 394,83 6 7 8 I 5. A process according to claim 4 comprising incorlower hydroxyalkyl,

porating into paper stock an effective amount of an with the proviso that at least one of R R and R, is aqueous solution of the compound of the formula lower hydroxyalkyh- H035 o Cu '-o O-C -O or a salt thereof, said effective amount being an amount 8. A process according to claim 4 comprising incorsufficient to impart the desired color to the paper sheet porating into paper stock an effective amount of a to be formed, and forming paper sheet from said paper granular composition comprising the compound of the stock. formula C 0 O CU -O 6. A process according to claim 5 wherein said aqueor a salt thereof, up to percent of non-hygroscopic ous solution comprises 1 part by weight of the comdextrin or at least one salt that dissociates in water, or pound of the formula a mixture thereof, with the proviso that the average size O- Cu -O SO H or a salt thereof, 3 to 11 parts by weight of water and of the granules is at least 20 microns, said effective 0.5 to 3 parts by weight of an amino alcohol.

7. A process according to claim 6 wherein said amino alcohol is a compound of the formula wherein each of R R and R is independently hydrogen or amount being an amount sufficient to impart the desired color to the paper sheet to be formed, and forming paper sheet from said paper stock.

9. A process according to claim 8 wherein said salt that dissociates in water is sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, monosodium phosphate, disodium phosphate, 7 sodium pyrophosphate, potassium pyrophosphate, sodium carbon- 23.6 or potassium carbonate and the average size of the granules is 40 to microns.

10. A process according to claim 4 comprising admixing an effective amount of the compound of the formula w s Cu -o N N N N H0 5 SO 3 H or a salt thereof, with cellulose in an aqueous medium from said paper stock. to form paper stock, said effective amount being an 11. Paper produced by the process of claim 1. amount sufiicient to impart the desired color to the l5 12. Paper produced by the process of claim 4. paper sheet to be formed, and forming paper sheet k a: 

1. A PROCESS FOR PRODUCING COLORED PAPER COMPRISING (A) INCORPORATING INTO PAPER STOCK AN EFFECTIVE AMOUNT OF A DYE AND FORMING PAPER FROM SAID PAPER STOCK OR (B) TREATING PAPER SHEET WITH AN EFFECTIVE AMOUNT OF A DYE, SAID DYE BEING THE COMPOUND OF THE FORMULA
 2. A process according to claim 1 comprising treating paper sheet with an effective amount of the compound of the formula
 3. A process according to claim 2 comprising applying to paper sheet an effective amount of an aqueous solution of the compound of the formula
 4. A process according to claim 1 comprising incorporating into paper stock an effective amount of the compound of the formula
 5. A process according to claim 4 comprising incorporating into paper stock an effective amount of an aqueous solution of the compound of the formula
 6. A process according to claim 5 wherein said aqueous solution comprises 1 part by weight of the compound of the formula
 7. A process according to claim 6 wherein said amino alcohol is a compound of the formula
 8. A process according to claim 4 comprising incorporating into paper stock an effective amount of a granular composition comprising the compound of the formula
 9. A process according to claim 8 wherein said salt that dissociates in water is sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, monosodiUm phosphate, disodium phosphate, sodium pyrophosphate, potassium pyrophosphate, sodium carbonate or potassium carbonate and the average size of the granules is 40 to 120 microns.
 10. A process according to claim 4 comprising admixing an effective amount of the compound of the formula
 11. Paper produced by the process of claim
 1. 12. Paper produced by the process of claim
 4. 